Lost urge to masturbate. lose erections in middle of foreplay. blood test and ultrasound are normal, doctor says in my head but i feel something's up.

Often psychogenic: Very often, once physical issues like hormonal imbalances and anatomical anomalies have been ruled out, it is a psychological problem in the end. There are some other factors, like smoking, drug use, alcohol use, or poor diet that can contribute. But if none of these seem like an issue, it really is most likely related to anxiety or other psychogenic issue. Consider seeking counseling.

Could be: Evaluation for depression or extreme stress or worries may be helpful especially if morning erection is still present

Some ideas: Two causes of erectile dysfunction that often affect young men and get missed by clinicians are prolactinoma and hemochromatosis.

Here are some ...: You need a comprehensive evaluation, which starts off with reviewing your general and sex history, lifestyle, possible drug use or abuse, functional output , erc. since the teenager + physical exam, + tests as needed as suggested by numerous doctors so to deduce possible causes for proposing reasonable Rx / care. Best wish ...